In production of a semiconductor device, processing steps such as a chemical vapor deposition (CVD) step, a surface modification step and the like are performed by use of a semiconductor production device including a substrate support device that supports a wafer, which is a semiconductor substrate. For heating the wafer, a substrate support device including a built-in heating element is used.
Such a substrate support device has a structure in which a plate formed of a metal or ceramic material is supported by a shaft. The substrate support device operates by the following mechanism. The plate includes a plasma electrode or a heating element provided therein. When an electric current is supplied to the heating element via a line located inside the shaft, the heating element is heated, and the wafer is heated by the heat generated in the heating element.
The wafer located on such a plate may possibly have a temperature higher than a desired temperature. In order to avoid this, a conventional substrate support device has a flow path formed in a wafer holder that holds the wafer, and supplies a fluid to the flow path so that the wafer holder is cooled to adjust the temperature of the wafer (see, for example, Japanese Laid-Open Patent Publication No. 2007-43042).
However, the above-described conventional substrate support device has the flow path for cooling located in only one surface of the plate. Therefore, it is difficult to uniformly heat the plate, and the plate itself may be deformed or may have any other fault due to thermal strain of the plate. This may cause malfunction of the substrate support device. In addition, the temperature of the wafer placed on the plate may be varied in the plane thereof. In the state where there is temperature variance in the plane of the wafer, the wafer may be curved or may have any other fault, which may decrease the yield of the semiconductor devices.
The present invention made to solve the above-described problems has an object of providing a substrate support device that, for heating a wafer, uniformly heats a heater plate so that the heater plate is not deformed or does not have any other fault due to thermal strain, and so that the temperature uniformity of the wafer is improved.